新型FRP-金属组合T型梁桥及扭转刚度简化计算方法的研究

Study on new FRP⁃metal composite T⁃type girder bridge and simplified calculation method of its torsional stiffness

基于应急桥梁的轻量化、高强化和模块化的发展需求,提出了一种模块化纤维增强复合材料(FRP)-金属组合T型梁桥。首先,介绍了该T型梁桥的结构尺寸、空间布置、杆件类型、连接方式以及现场快速架设方法。其次,基于开口、闭口薄壁截面杆扭转理论,推导了该T型梁桥结构扭转刚度简化计算公式。最后,基于通用软件ANSYS开展了有限元分析,利用所推导的简化计算公式进行了结构扭转刚度影响因素分析。结果表明:相较于传统单车道钢结构应急桥梁,该组合T型梁桥达到了明显的减重效果;结构扭转刚度理论计算值与有限元值吻合较好,所建立的理论简化计算模型可便于单片T型梁扭转刚度的预测;单片T型梁的外扭矩主要由各纵向构件和斜腹杆共同抵抗。

Based on the development requirements of lightweight,high⁃strength and modularization of emergency bridges,a modular fiber⁃reinforced⁃polymer(FRP)⁃metal T⁃type girder bridge was proposed.The structure sizes,spatial layouts,member types,connection type and rapid erection methods of the hybrid T⁃type girder bridge were firstly introduced.Secondly,based on the torsion theory of open and closed thin⁃walled cross⁃section rods,a simplified calculation formula for structural torsional stiffness was derived.Finally,the corresponding numerical analysis was carried out based on the general software ANSYS,and the influence factors of structural torsional stiffness were analyzed based on the simplified calculation formula.The results indicate that:compared with the traditional single⁃lane steel emergency bridge,the hybrid T⁃type girder bridge shows an obvious weight reduction;the theoretical solutions of structural torsional stiffness coincide well with the computed values,and the simplified theoretical model can thus be used to predict the torsional stiffness of the single T⁃type girder;the torsional moment of the single T⁃type girder is mainly resisted by torsion of longitudinal members and web diagonal members.